FAST-LIO2

Introduction

FAST-LIO2 is a fast, robust, and versatile LiDAR-inertial odometry framework. Building on a highly efficient tightly-coupled iterated Kalman filter, FAST-LIO2 has two key novelties that allow fast, robust, and accurate LiDAR navigation (and mapping). The first one is directly registering raw points to the map (and subsequently update the map, i.e., mapping) without extracting features. This enables the exploitation of subtle features in the environment and hence increases the accuracy. The elimination of a hand-engineered feature extraction module also makes it naturally adaptable to emerging LiDARs of different scanning patterns; The second main novelty is maintaining a map by an incremental k-d tree data structure, ikd-Tree, that enables incremental updates (i.e., point insertion, delete) and dynamic re-balancing. Compared with existing dynamic data structures (octree, R*-tree, nanoflann k-d tree), ikd-Tree achieves superior overall performance while naturally supports downsampling on the tree. Overall, FAST-LIO2 is computationally-efficient (e.g., up to 100 Hz odometry and mapping in large outdoor environments), robust (e.g., reliable pose estimation in cluttered indoor environments with rotation up to 1000 deg/s), versatile (i.e., applicable to both multi-line spinning and solid-state LiDARs, UAV and handheld platforms, and Intel and ARM-based processors). Here are some reference links: code link. paper link.

Evaluation

Platforms	Sequences	Length(m)	ATE when using Mid-360	ATE when using VLP-32C
A Handheld	Escalator	77.460	ground truth	0.627438
	MCR normal dark	76.499	0.035	0.034
	MCR aggressive 6dof light	100.871	0.204	0.033
	Parkway loop night	461.049	26.351	18.834
	Forest	130.937	ground truth	1.031
A UGV	Elevator	39.336	X	X
	Indoor loop	270.674	ground truth	0.116
	MCR hdr	193.918	0.039	88.059
	Street day	2064.475	6.171	5.893
	Parkway loop night	461.051	13.747	12.129
A QR	Underground	98.312	ground truth	0.032
	MCR hdr	85.08	0.062	0.841
	Forest	108.037	ground truth	0.045
A UAV	MCR loop light	104.989	No Mechanical LiDAR	0.026
A Car	Urban night loop	1807.884	3.291	No Solid-State LiDAR